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1863 Antinous
1863 Antinous , provisional designation , is a stony asteroid and near-Earth object, approximately 2–3 kilometers in diameter. It was discovered on 7 March 1948 by American astronomer Carl Wirtanen at Lick Observatory on the summit of Mount Hamilton, California. It was named after Antinous from Greek mythology. Orbit and classification ''Antinous'' is also classified as a Mars-crosser and Apollo asteroid. The SU/Sq-type asteroid orbits the Sun in the inner main-belt at a distance of 0.9–3.6 AU once every 3 years and 5 months (1,240 days). Its orbit has an eccentricity of 0.61 and an inclination of 18 ° with respect to the ecliptic. It has an Earth ''Minimum orbit intersection distance'' (MOID) of 0.1836 AU. In the 20th century ''Antinous'' passed within 30 Gm of the Earth five times; it will do so only once in the 21st. The nearest distance increases each time, from 26 to 29 Gm. Physical characteristics In the Tholen and SMASS taxonomic scheme, ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carl Wirtanen
Carl Alvar Wirtanen (November 11, 1910 – March 7, 1990) was an American astronomer and discoverer of comets and minor planets who worked at Lick Observatory. He was of Finnish ancestry. Wirtanen was born in Kenosha, Wisconsin. After visiting the observatory in Kenosha with his violin teacher at age 12, he started grinding mirrors. Wirtanen joined the staff at Lick Observatory in 1941. During the Second World War, he took a job as a physicist at the California Institute of Technology and worked on ballistics at the Naval Ordnance Test Station in the Mojave Desert. He returned to Lick Observatory after the war, remaining there until his retirement in 1978. Wirtanen discovered periodic comet 46P/Wirtanen, as well as eight asteroids, including notably the Apollo asteroid (29075) 1950 DA, which may have a non-negligible probability of impacting the Earth in the year 2880. He also discovered two other Apollo asteroids: 1685 Toro and 1863 Antinous. Based on the ''Shane–Wirtanen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mars-crosser Asteroid
A Mars-crossing asteroid (MCA, also Mars-crosser, MC) is an asteroid whose orbit crosses that of Mars. Some Mars-crossers Minor planet designation, numbered below 100000 are listed here. They include the two numbered Mars trojans 5261 Eureka and . Many databases, for instance the JPL Small-Body Database (JPL SBDB), only list asteroids with a perihelion greater than 1.3 Astronomical Unit, AU as Mars-crossers. An asteroid with a perihelion less than this is classed as a near-Earth object even though it is crossing the orbit of Mars as well as crossing (or coming near to) that of Earth. Nevertheless, these objects are listed on this page. A grazer is an object with a perihelion below the aphelion of Mars (1.67 AU) but above the Martian perihelion (1.38 AU). The JPL SBDB lists 13,500 Mars-crossing asteroids. Only 18 MCAs are brighter than Absolute magnitude#Solar System bodies (H), absolute magnitude (H) 12.5, which typically makes these asteroids with H<12.5 more than 13 km in d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1143 Odysseus
1143 Odysseus , provisional designation ', is a large Jupiter trojan located in the Greek camp of Jupiter's orbit. It was discovered on 28 January 1930, by German astronomer Karl Reinmuth at the Heidelberg Observatory in southwest Germany, and later named after Odysseus, the legendary hero from Greek mythology. The dark D-type asteroid has a rotation period of 10.1 hours. With a diameter of approximately , it is among the 10 largest Jovian trojans. Orbit and classification ''Odysseus'' is a dark Jovian asteroid orbiting in the leading Greek camp at Jupiter's Lagrangian point, 60 ° ahead of the Gas Giant's orbit in a 1:1 resonance ''(see Trojans in astronomy)''. It is a non-family asteroid in the Jovian background population. It orbits the Sun at a distance of 4.8–5.7 AU once every 12 years (4,393 days; semi-major axis of 5.25 AU). Its orbit has an eccentricity of 0.09 and an inclination of 3 ° with respect to the ecliptic. As a Jupiter Trojan it is in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
201 Penelope
Penelope (minor planet designation: 201 Penelope) is a large Asteroid belt, main belt asteroid that was discovered by Austrian astronomer Johann Palisa on August 7, 1879, in Pula, Pola. The asteroid is named after Penelope, the wife of Odysseus in Homer's ''The Odyssey''. It is orbiting the Sun at a distance of with an orbital eccentricity, eccentricity (ovalness) of 0.18 and a orbital period, period of . The orbital plane is tilted at an angle of 5.8° to the plane of the ecliptic. Based upon the spectra of this object, it is classified as a M-type asteroid, indicating it may be metallic in composition. It may be the remnant of the core of a larger, differentiated asteroid. Near infrared absorption features indicate the presence of variable amounts of low-iron, low-calcium orthopyroxenes on the surface. Trace amounts of water is detected with a Mass fraction (chemistry), mass fraction of about 0.13–0.15 wt%. It has an estimated size of around 88 km. With a rotation period ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minor Planet
According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''minor planet'', but that year's meeting reclassified minor planets and comets into dwarf planets and small Solar System bodies (SSSBs).Press release, IAU 2006 General Assembly: Result of the IAU Resolution votes International Astronomical Union, August 24, 2006. Accessed May 5, 2008. Minor planets include asteroids ( |
Geometric Albedo
In astronomy, the geometric albedo of a celestial body is the ratio of its actual brightness as seen from the light source (i.e. at zero phase angle) to that of an ''idealized'' flat, fully reflecting, diffusively scattering ( Lambertian) disk with the same cross-section. (This phase angle refers to the direction of the light paths and is not a phase angle in its normal meaning in optics or electronics.) Diffuse scattering implies that radiation is reflected isotropically with no memory of the location of the incident light source. Zero phase angle corresponds to looking along the direction of illumination. For Earth-bound observers, this occurs when the body in question is at opposition and on the ecliptic. The visual geometric albedo refers to the geometric albedo quantity when accounting for only electromagnetic radiation in the visible spectrum. Airless bodies The surface materials (regoliths) of airless bodies (in fact, the majority of bodies in the Solar System) are stro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotation Period
The rotation period of a celestial object (e.g., star, gas giant, planet, moon, asteroid) may refer to its sidereal rotation period, i.e. the time that the object takes to complete a single revolution around its axis of rotation relative to the background stars, measured in sidereal time. The other type of commonly used rotation period is the object's synodic rotation period (or ''solar day''), measured in solar time, which may differ by a fraction of a rotation or more than one rotation to accommodate the portion of the object's orbital period during one day. Measuring rotation For solid objects, such as rocky planets and asteroids, the rotation period is a single value. For gaseous or fluid bodies, such as stars and gas giants, the period of rotation varies from the object's equator to its pole due to a phenomenon called differential rotation. Typically, the stated rotation period for a gas giant (such as Jupiter, Saturn, Uranus, Neptune) is its internal rotation period, as d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gigametre
The following are examples of order of magnitude, orders of magnitude for different lengths. __TOC__ Overview Detailed list To help compare different orders of magnitude, the following list describes various lengths between 1.6 \times 10^ metres and 10^metres. Subatomic scale Atomic to cellular scale Cellular to human scale Human to astronomical scale Astronomical scale Less than 1 zeptometre The ' (SI symbol: ') is a Units of measurement, unit of length in the metric system equal to . To help compare different orders of magnitude, this section lists lengths shorter than 10−21 metre, m (1 zm). *1.6 × 10−5 quectometres (1.6 × 10−35 metres) – the Planck length (Measures of distance shorter than this do not make physical sense, according to current theories of physics.) *1 qm – 1 quectometre, the smallest named subdivision of the metre in the SI base unit of length, one nonillionth of a metre *1 rm – 1 rontometre, a subdivision of the metre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minimum Orbit Intersection Distance
Minimum orbit intersection distance (MOID) is a measure used in astronomy to assess potential close approaches and collision risks between astronomical objects. It is defined as the distance between the closest points of the osculating orbits of two bodies. Of greatest interest is the risk of a collision with Earth. Earth MOID is often listed on comet and asteroid databases such as the JPL Small-Body Database. MOID values are also defined with respect to other bodies as well: Jupiter MOID, Venus MOID and so on. An object is classified as a potentially hazardous object (PHO) – that is, posing a possible risk to Earth – if, among other conditions, its Earth MOID is less than 0.05 AU. For more massive bodies than Earth, there is a potentially notable close approach with a larger MOID; for instance, Jupiter MOIDs less than 1 AU are considered noteworthy since Jupiter is the most massive planet.Bruce Koehn,Minimum Orbital Intersection Distance, Lowell Observatory, retrieved o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecliptic
The ecliptic or ecliptic plane is the orbital plane of the Earth around the Sun. From the perspective of an observer on Earth, the Sun's movement around the celestial sphere over the course of a year traces out a path along the ecliptic against the background of stars. The ecliptic is an important reference plane and is the basis of the ecliptic coordinate system. Sun's apparent motion The ecliptic is the apparent path of the Sun throughout the course of a year. Because Earth takes one year to orbit the Sun, the apparent position of the Sun takes one year to make a complete circuit of the ecliptic. With slightly more than 365 days in one year, the Sun moves a little less than 1° eastward every day. This small difference in the Sun's position against the stars causes any particular spot on Earth's surface to catch up with (and stand directly north or south of) the Sun about four minutes later each day than it would if Earth did not orbit; a day on Earth is therefore 24 hours ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Inclination
Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Earth directly above the Equator, the plane of the satellite's orbit is the same as the Earth's equatorial plane, and the satellite's orbital inclination is 0°. The general case for a circular orbit is that it is tilted, spending half an orbit over the northern hemisphere and half over the southern. If the orbit swung between 20° north latitude and 20° south latitude, then its orbital inclination would be 20°. Orbits The inclination is one of the six orbital elements describing the shape and orientation of a celestial orbit. It is the angle between the orbital plane and the plane of reference, normally stated in degrees. For a satellite orbiting a planet, the plane of reference is usually the plane containing the planet's equator. For pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Eccentricity
In astrodynamics, the orbital eccentricity of an astronomical object is a dimensionless parameter that determines the amount by which its orbit around another body deviates from a perfect circle. A value of 0 is a circular orbit, values between 0 and 1 form an elliptic orbit, 1 is a parabolic escape orbit (or capture orbit), and greater than 1 is a hyperbola. The term derives its name from the parameters of conic sections, as every Kepler orbit is a conic section. It is normally used for the isolated two-body problem, but extensions exist for objects following a rosette orbit through the Galaxy. Definition In a two-body problem with inverse-square-law force, every orbit is a Kepler orbit. The eccentricity of this Kepler orbit is a non-negative number that defines its shape. The eccentricity may take the following values: * circular orbit: ''e'' = 0 * elliptic orbit: 0 < ''e'' < 1 * [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
